September 26, 1968 -HW-16 Novice Transmitter Bulletin No:  HW-16-1. Side Tone - When using the HW-16 with a VFO sometimes a partial operation of the sidetone oscillator takes place due to an increased loading on the bias voltage.  This can be corrected by changing R-69 from a 120K ohm resistor to a 220K ohm resistor [PN 1-29].  Also, the original schematic shows R-16 as a 4700 ohm resistor which is incorrect.  R-16 should be shown as a 5600 ohm resistor.
September 9, 1971-HW-16  Novice Transmitter Bulletin No: HW-16. Resistor Failure Due to repeat failure of a resistor in the field, the following change should be made in all units being serviced.  CHANGE:  R21 22K 1 Watt to 2 Watt [PN 1-11-2].